Components are used to execute custom business Logic in a Mule application. Most components will are bespoke and are written according to application requirements. However, Mule does ship with a number of components that allow you to execute BPEL, Rules, Scripts and more inside Mule.

BPEL Component - Execute BPEL processes using PXE BPEL engine.

REST Service Wrapper - Proxy remote call to REST style web services as local components.

Scripting Component - Run scripts (JSR-223) as Mule components.

Simple components

These are useful for testing -

1. EchoComponent - will send back whatever you send it. Can be found at org.mule.components.simple.EchoComponent.
2. LogComponent - Will log any events it receives to the console. Can be found at org.mule.components.simple.LogComponent.
3. NullComponent - Will throw an exception if invoked. This is used when setting up a forwarding/pipeline component where a message is received on one endpoint and piped directly to another without invoking a component. Can be found at [org.mule.components.simple.NullComponent |http://mule.codehaus.org/docs/apidocs/org/mule/components/simple/NullComponent .html].